The present invention relates to a device for rapidly locking and centering core boxes on respective supporting plates, particularly indicated for use in automatic molding sand core-forming machines.
As is known, machines for forming cores in molding sand use openable dies, that is, dies composed of two half-dies mounted on adapted supports so as to allow the mating closing approach thereof, thus allowing their filling with sand which is thrown or shot under pressure through a launch head, and subsequently opened by moving apart both the half-dies or one thereof with respect to the other, so as to allow extraction of the formed core.
Generally, these half-dies are supported by box-like containment body, commonly known as "core box", which is supported by, and removably rigidly connected to, a quadrangular plate peripherally provided with a raised border with quadrangular cross section so as to define a planar resting and fixing frame for the core box, said frame being substantially formed by supporting plates with a limited extension.
Correct positioning and stable locking of core boxes on respective supporting plates in currently achieved by means of locating pegs facilitating their positioning and of a plurality of locking screws, arranged in various manners and in various accessible positions.
Since change and replacement of core boxes is, at least in some kind of processes, rather frequent, the presence of a plurality of screws to be operated entails considerable work times which are to be considered as substantially idle times, that is, unproductive.
Moreover, the provision of a plurality of threaded holes with related screws in practice entails difficulties in design and manufacture which also influence the overall cost of the core boxes and of the supporting plates, besides requiring regular maintenance and availability of screws and tools for their application.
Thus, the complexity due to the plurality of locking screws and the economic burdens which in practice derive therefrom substantially affect negatively the productivity of the forming machine and its practicality in use.